Tyrosine Kinases are a class of enzymes, which catalyze the transfer of the terminal phosphate of adenosine triphosphate to the phenolic hydroxyl group of a tyrosine residue present in the target protein. Tyrosine kinases play a critical role in signal transduction for several cellular functions including cell proliferation, carcinogenesis, apoptosis, and cell differentiation (Plowman, G. D.; Ullrich, A.; Shawver, L. K.: Receptor Tyrosine Kinases As Targets For Drug Intervention. DN&P (1994) 7: 334-339). Therefore inhibitors of these enzymes would be useful for the treatment or prevention of proliferative diseases which are dependent on these enzymes. Strong epidemiologic evidence suggests that the overexpression or activation of receptor protein tyrosine kinases leading to constitutive mitogenic signaling is an important factor in a growing number of human malignancies. Tyrosine kinases that have been implicated in these processes include Abl, CDK's, EGF, EMT, FGF, FAK, Flk-1/KDR, HER-2, IGF-1R, IR, LCK, MEK, MET, PDGF, Src, and VEGF (Traxler, P. M. Protein Tyrosine Kinase Inhibitors in Cancer Treatment. Exp. Opin. Ther. Patents (1997) 7: 571-588; incorporated herein by reference). Hence, there is an ongoing need to investigate novel compounds that can be used to regulate or inhibit tyrosine kinase enzymes.